A natural phenomenon picked up as a radio signal from outer space, and sounding like a loud hiss.

The dark space in a glow discharge that is adjacent to the cathode.

The dark space in a glow discharge that is between the negative glow and the positive column.

The dark space in a glow discharge between the cathode glow and the negative glow.

The official name of Spain.

Melospiza melodia, a medium-sized American sparrow.

plural of Spanish fly

(topology) A space for which properties like uniform continuity and uniform convergence can be formulated.

(topology) A space for which notions of a Cauchy sequence and completeness exist.

(mathematics, physics) A four-dimensional real vector space equipped with an inner product of signature (−,+,+,+) or (+,−,−,−), in which special relativity is formulated